A color cathode ray tube uses an aperture grill having a plurality of color selective electrodes (grill tapes) which are obtained by forming a number of vertical stripe slits on a metal plate by selective etching. In the color cathode ray tube of this type, the grill tapes can be vibrated by a loud sound or impact, thereby resulting in a deterioration in image quality.
To reduce this problem, a damper wire is horizontally stretched along the aperture grill surface to prevent vibration of the grill tape. The number of the damper wires can be one or more. For example, one for a small sized tube of 14 to 16 inches; two for a medium sized tube of 18 to 25 inches; and three for a large sized tube of 25 inches or more.
Conventionally, the above-described stretching of a damper wire has been manually performed.
The manual stretching of a damper wire creates problems in that the stretching operation takes a relatively long amount of time, requires an operator of a very high skill level, and results in a product of variable quality.